Miniature electric freezer



Dec. 12, 1961 F. A. HILL 2ND 3,012,418

MINIATURE ELECTRIC FIREEZERv Dec. 12, 1961 F. A. HILL 2ND 3,012,418

MINIATURE ELECTRIC FREEZER Filed Jan. s, 1958 3 sheets-sheet 2 JNVENTORM Dec. 12, 1961 F. A. HILL 2ND 3,012,418

MINIATURE ELECTRIC FREEZER Filed Jan. 8, 1958 3 Sheets-Sheet 3 PLASTIC BUCKET TO HOLD WATER F COOLING CONDENSER TUBES FIG. 8-

IN V EN TOR.

Unit: States iggi Patented Dee. l2, 1351 512,418 NENIATURE ELECTRIC FREEZER Francis A. Hill 2nd, 23 tiempo Parkway, Westport, Conn. Fiied Stan. 8, i958, Ser. No. 'MV/,764i 9 Claims. (Qi. 62u56@ My invention relates to a miniature portable electric freezer. lt will freeze from one to three ice cubes in five to fifteen minutes. It weighs less than 6 pounds and can be carried in a suitcase while travelling. It can be used on small yachts and as a toy for children.

One of the objects of my invention is to provide for rapid cooling of the compressed hot refrigerating gases with the least amount of radiating surface.

A second object of my invention is to provide means for cooling the electric motor.

A third object of my invention is to provide means to cool the electric motor with part of the compressed and condensed refrigerant.

A fourth object of my invention is to provide means for two stages of compression.

A fifth object of my invention is to provide a cornpressor whichis essentially two cycle in operation.

-A sixth object of my invention is to provide a miniature electric freezer with the parts so arranged that the condenser coils, the compressor and the electric motor may be immersed in water and cooled.

ln the gures:

FlG. l is a vertical sectional elevation of my miniature freezer on line 1 1, FIG. 2, using an opposed piston compressor.

FIG. 2 shows a sectional View of my freezer on line 2 2 in FIG. l.

FIG. 3 shows a pair of Rotoid gears which can be used for compressing a refrigerant gas.

FIG. 4 is a bottom view of the freezer using a two stage piston compressor with a cooling coil between the stages on line 4-4 in FIG. 5.

FIG. 5 is a right hand view of FIG. 4 with the outer shell in section.

FIG. 6 is a vertical section showing the gears in FIG. 3 at the bottom end of my miniature freezer.

FIG. 7 is an inside view of the bottom port plate in FIG. 6.

FIG. 8 shows a simpler construction than in FIG. l, a two-way valve, and an internal gas cooling circuit for the motor.

FIG. 9 shows an outer shell with inner ribs arranged so as to permit expansion of internal members without undue stress.

FIG. l0 shows a four section ice tray for four pieces of 1ce.

When travelling in Europe few hotels and motels have the ready quantities of ice to which we are accustomed in America. A freezer which is light to carry and which can malte a few cubes of ice quickly will be very useful. For this reason l show it set in a wash basin A with running water from a faucet B to cool the condenser coil 23. The water can overflow at C and down the drain pipe at D. ln FIG. l the cylindrical casing 1 contains the ice tray 2 and cover 3, evaporator 4, insulated chamber 5, motor 7 inside a hermetically sealed inner casing 32 with a drive shaft 8 projecting into a compressor housing 9 with cover 9A. This housing 9 has a cylindrical iiange 9B enclosing and sealing the casing 1 and is cooled by water when in the basin of water A. The other end.

of the casing 1 is sealed by the member 5A. On the shaft 6 is rigidly mounted an eccentric 10 carrying the pin Il which engages the link i2 which has another pin 13 which engages the opposed piston member i4. Rotation of the shaft 8 causes piston member 14 to reciprocate in its cylinders 27A and 28A in the housing 9. The left end of piston 14 is shown at the end of its compression stroke and the right end at the end of the suction stroke with the intake port uncovered completely. The pocket 14C acts as an oil reservoir. It holds enough oil to lubricate the piston member 14 while reciprocating.

At the outer end of each compressor cylinder 28A and 27A are valves l5 and 16 held in position by springs 17 and l. Cylinder caps 19 and 20 close the ends of the cylinders. During compression the valves 15 and 16 lift to permit compressed refrigerant to escape into pasageways 2l and 22. Passageways 21 and 22 connect with an annular groove 23 in the housing 9. Groove 23 acts as a receiver and the gas in it is cooled by the shell 1 and the water outside of it in the basin A in FIG. 1. Gas in the groove 23 and whatever condensed refrigerant there may be iiows up through coil 24 where it is cooled some more and into the evaporator 4 where it is restricted by a capillary tube 25. From 4 the gas returns to the compressor by the conduit 26. 26 connects into another annular groove 26A in housing 9. Passageways 26B and 26C return the gas to the intake ports 27 and 28. Opening 26D allows oil to spill out and down into the reservoir 314C.

In my miniature freezer the piston will have a diameterand stroke of about 3/6 of an inch. Cylinder clearances can be reduced to zero by having the Valves 15 and 16 close to the ends of the cylinders and having the outer ends of the piston practically ush with the outer ends of the cylinders at the ends of the compression strokes.

The intake ports 27 and 28 are uncovered when the pistons approach the low pressure ends of the cylinders and are covered again a short bit after the start of the compression strokes. Since there are two compression strokes per revolution power from the motor is used throughout each rotation of 360. The power required is that needed for compression in one cylinder plus the small amount of power to create the vacuum in the other before the intakes are uncovered. In this construction the same size motor can be used for two pistons and cylinders as for one piston and cylinder. This is especially true when the motor has the usual reserve power of a well designed unit.

The freezer casing Il has openings 29 for the circulav tion of cooling water around the coils 24. Openings 29 permit water circulation around th compressor housing 9 (FIGS. 1 and 5).

The motor 7 is inside a hermetically sealed casing 32 which is cooled on its outside by water between it and the condenser coils 24. By having the motor in contact thermally with the casing 32 it is cooled also. This motor is of a sub-fractional horse power between 1go and Vg@ depending upon the sizes of the pistons. It can be connected to a source of electricity by the cord E passing from the motor thru a gas tight joint in the casing wall 32 and out thm i. In order to avoid bursting mechanical stresses on the casing 32 ribs 33 (FIG. 9) set at an angle to the radius R which can flex a few thousandths of an inch as indicated by the arrows 34 to relieve the outward expansion of the motor 7 in the direction of the arrow 35.

When additional condensing surface is needed another spiral coil 24A (shown in dotted lines) can connect the compressed discharged refrigerant in the annular groove 23 (by spiralling upward between the coils 24) with the Junction 2st-B.Y rfhe compressed condensed refrigerant from both coils 24 and 24A then enters the evaporator 4.

FIG. 8 is partly in section and partly schematic. It shows my miniature freezer without an outer shell. Condenser pipes 36 and 37 (similar to 24 and 24A in FlG. l) deliver refrigerant to a two way valve 3S near the top of the freezer. When the valve piston 39 is in the position shown in solid iines, condensed refrigerant from 37 enters tical.

smears spaces and thru holes 66 and into groove 26A (indicated by arrow 66A) and into the intake ports 27 and 28 as shown in FIG. 1.

When the valve piston is pushed to the right as shown in dotted lines, the condensed refrigerant from 36 joins Vthat from 37 and enters the evaporator as described above. Conduit 61 returns the gas from the evaporator to the annular groove 26A.

In FIG. 4 I show a two stage compressor. The right hand piston 14A compresses gas for the rst stage from whence it goes out of the discharge port at 22 into the cooling coil 21A and then to the intake 29 for the second stage of compression by the piston 14B and delivered to the condenser coil 24 in FIG. 1. The coil 22A is of course cooled by the water in the basin. This basin need not be 'a wash basin. It can be a dish pan or a pail of water. When the water gets too warm it can be dumped out and fresh water put in. When the freezeris made of corrosion resistant enamel salt water can be used as the cooling Huid when in a boat on the sea.

FIG. 3 shows a pair of Rotoid gears (Pat. No. 2,666,- 336). FIG. 6 is a. vertical section thru a Rotoid compressor showing the inner gear 50 having 5 teeth and the outer gear S1 having 7 teeth. 50 is journalled onthe fixed shaftV 53. 51' is mounted on the back plate V52 which isrkeyed to and driven by a ymotor shaft 54 jonrnalled in the housing 59 at 55. This housing 59 has a ange Y59B enclosing and sealing the compressor end of the casing 1. The intake port is indicated at 58 and the discharge port at 57 in FIGS. 6 and 7. The return tube 26 connects with the intake port 58.Y The discharge port 57 connects with the condenser coil 24. TheseV gears are inherently two cycle in action.

This miniature freezer is not much larger than the drawin FIGURE 8. The top of theV piastic bucket indicates the preferred level of the water when the urn't is partially immersed. Y

I do not limit my invention to the particular construction shown. The motor mayl be horizontal instead of ver- The condenser coil or coils may be inside or outside ofthe casing 1. Other types of compressors may be used. The essence of my invention consists of a miniature freezer which has to be set in water in order to cool the condensing gases, to cool the electric motor and to cool the compressor. To be suliciently light Yand portable my miniature freezer has to be designed without adequate cooling means. VThe user must supply thebath of water in which'to immerse the'little freezer so that the refrigeration cycleV will be eicient. 'Y

, What I ciaim is:

1. In a miniature portable freezing unit, a casing, any

ice chamber at one end of said casing, a loose fitting cover for said ice chamber, an expansion chamber containing a capillary tube and adjacenttoV said ice chamber andV hermetically sealing said casing, a motor driving and attached to a compressor inside said casing, a housing for 4said compressor hermetically sealing the opposite endV of said casing, the outer surfaceV of said motor being in contact with the inner surface of said casing, intake and discharge ports for said compressor, conduits between said ports and said expansion chamber and said capillary tube,

and having the surface of said motor and conduits containing hot refrigerant Vcooled when said miniature portable freezing unit is in contact with and partially immersed in a separate and unattached body of cooling water. v

2. The combination according to claim l, and having Va container separate andY detached from said freezing unit for holding said body of water.

3. The combination according to claim 1, and having a pocket for holding a lubricant in said compressor in said housing. Y

4. The combination according to claim 1, said compressor comprising two opposed pistons in line with each other and'rigidly connected together, a rst member engaging said pistons, a ysecond member mounted eccentrically'to the drive shaft of said motor, a link engaging said rst and second members so as to cause said pistons to reciprocate when said shaft rotates and carries said second member around during each revolution, counter balancing means on said shaft, discharge valves at the ends of each cylinder of said compressor pushed olf their seats by the compressed gas during discharge and returned to their seats shortly after the start of the intake stroke by springs, intake ports near the other ends of said cylinders and uncovered by said pistons near the end of the intake stroke and closed by said pistons shortly after the start of the compression stroke. f

5. The combination according to claim 1, and having compressed refrigerant iiow through two conduits between the compressor and the expansion chamber.

6. The combination according 'to` claim 1, having two grooves around the housing of said compressor, one groove connected to the intake port or ports and the other connected to the discharge port or ports, each of said groovesA being closed by a casing inner surface so that the refrigerant in said grooves is cooled by said casing when said miniature freezer is immersed in water.

7. The combination according to claim 1, two conduits from said compressor containing compressed discharged and condensed refrigerant connected to a two way valve, said valve having two settings, one to send said refrigerant in both of said conduits into said expansion chamber and the other to send the refrigerant from one conduit into said expansion chamber andthe refrigerant from the other of said conduits into the inside of said casing containing said motor, and having passageways connecting to the intake of said compressor.

8. The combination according to claim 1 having a seco nd casing outside of and surrounding said casing containing said motor and compressor, and openings in said second casing to permit Water to come in contact with the outside of said casing containing said motorand compressor.

9. The combination according to claim 1, said compressor consistingof two opposed pistons connected together, one piston being a large piston for a iirst stage Yof compression and the other a smaller piston for a second stage of compression, means tol drive said pistons,'a coolingV conduit Lbetween the cylinders of said pistons, said conduit being cooled by water outside of said casing when said freezer is immersed and when refrigerant flows from the larger to the smaller cylinder. i 

